halsey



('N'o Model.)

, P. A. HALSEY.

VALVBGEAR FOR .ROCK DRILLS. No. 295,003.- Patented Mar. 11, 1884.

N4 PETERs Prwlulhagnpher. wnninsmn. D. t:A

linjrrn Y Sfrnrns nrnn'r einen.

FREDERIC A. HALSEY, OF NEW YORK, N. Y., ASSIGN OR TO THE RAND DRILL COMPANY,

or SAME PLACE.

VALVE-GEAR FOR ROCK-DRILLS.

SPECIFICATION forming part of Letters Patent No. 295,003, dated March 11, 1884.

v Application tiled January 17, 1884. (No'model.)

, T all whom, t may concern.-

Be it known that l, FREDERIC A. HALSEY, late ofNew Brighton, New York, now of the city of New York, in the county and State of New York, and a citizen of the United States of America, have invented an Improvement in the Valve-Gear of Steam RockDri1ls and Analogous Machines, of which the following is a specification.

The accompanying drawings represent a rock-drill embodying my invention, Figure 1 being a longitudinal'section (the piston in relief) on line y y, Fig. 2, and Fig. 2 a cross-section on line c as, Fig. 1.

For clearness of illustration the lower portions ot Fig. 1 represent as in a vertical plane thatportion of the liney y which extends obliquely upwardV from the center of the cylinder, and then horizontally outward through the nozzle for connection with the steam-pipe.

. In this class of en gines the piston makes strokes of variable length, because ofthe variation of the point of collision of the ltool with the rock or other object, and because of the variable feed of the tool to its work. As these machines have been heretofore constructed, whenever the piston, in its downward or working stroke, passes beyond the point intended to be the'limit of the shortest working-stroke which in practice it is permitted to make, it cushions upon steam prematurely introduced into the cylinder to effect the return or upward stroke, thereby diminishing the force of its longer strokes. ,It is necessary that at the end of its shortest stroke means should be brought into operation which will effect the opening of the inlet-port to the lower end of the cylinder by the time the piston reaches the end of the cylinder; otherwise a returnstroke would not be made and the piston would stop. Heretofore the said inlet-port has been actually opened and the steam let into the cylinder at this point. Vhen longer strokes are made under these conditions, the piston cushions upon the steam admitted between the time of the opening'oi the port and the end of such longer stroke, which will obstruct the piston and diminish the force of the blow struck. My present invention has relation to the diminishing of this obstruction to the piston in making its longer working-strokes by delaying the actual admission of steam to the lower end of the cylinder after the piston reaches the point of its shortest stroke, while at that point means are broughtA into opera tion which will effect the opening of the inlet-passage to the lower end of the cylinder by the time the piston reaches the end of its longer stroke. On the 26th day of October, 1883, I filed in the Patent Office an application, No. 110,082, for Letters Patent for means and the method by which the said object is effected. My present invention is an improvement thereon, and it consists in the special devices einployed for the purpose herein described and claimed.

Referring to the drawings, Ais asteam rockdrill cylinder provided with a piston, B, that, as shown, is elongated sufficiently to perform the offices hereinafter described, as well as those of a piston proper.

C is the piston-rod which carries the drill. The middle portion of the piston is circumferentially grooved, and the annular space E, between the grooved portion and the wall of the cylinder, serves as the steam-chest, receiving steam Athrough. the nozzle E, projecting from the side of the cylinder, as shown in Fig. 2.

E2 is a longitudinal groove in the cylinder, forming a chamber communicating with the chamber E and the nozzle E.

Fis the valve-chest, provided with a circumferentially-grooved valve, G, said valve having three grooves, forming in the valve-chest separate annular steam-spaces c c ci, and forming separate heads or `cylindrical portions c c c2 c, which make steam-tight joints with the cylindrical walls of the' valve-chest. valve-chest is also cireumferentially grooved internally, forming the annular steam-spaces bbbgi'.

t' and hare the ports communicating between the valve-chest andthe respective ends of the cylinder, the ends opening into the valvechest being governed by the valve. These passages serve both as inlet and exhaust ports.

D2 and D3 are inlet-passages governed by the piston, which communicate between the steamspace E and the valve-chest, for conducting steam from E to the valve-chest, where it is distributed by the ports D D.

The

IOC

.I is the exhaust-port from the lower end of the cylinder, and H2 is the exhaust-port for the upper end of the same.

H and H are respectively the exhaust-ports from the upper and the lower ends of the valvechest, opening at their inner ends into the cylinder and governed by the piston.

I and I are twoopen steam-passages, both communicating with the steam-space E2, and respectively with the opposite ends of the valve-chest. rIhese passages establish open and constant communication between the nozzle E (to be connected to the steam-supply pipe) and the two ends of the cylinder, whereby the two ends of the valve are constantly subjected to substantially an equilibrium of the full steampressure when the exhaust-ports H and H are closed. Under these conditions the valve will of course remain at rest in any given position. If, now, either exhaust-port is opened, the pressure being removed at the end at which the exhaust takes place, the valve will be shifted to that end, and there remain until such exhaust is closed and the exhaust at the opposite end ofthe chest is opened, when the valve will be reversed and shifted to the said opposite end. With this arrangement of parts I make the inlet-port to the lower end of the valve-chest ofcorrespondingly small cross-area or conducting capacity, so that the transmission through it of sufficient steam to shift the valve will occupy a determinate interval of time in order to permit the piston to move beyond the point of the shortest stroke, which in practice it is intended to make, to the end of 'its longer strokes by the time the steam is admitted into the lower end of the cylinder. The exhaust-ports H H are located relatively to the piston, as shown, so that the piston, in its downward stroke, will uncover the port just when the piston reaches the point of its shortest working-stroke, and will uncover the port H at the termination of its upstroke. Upon the opening of the exhaust H, with the valve at the lower end of the valve-chest, the pressure being relieved at the upper end ofthe valve, live steam will commence its transmis-` sion through the restricted passage at the lower end, and as soon as sufficient steam makes its way to the valve to overcome its inertia and friction the valve will be reversed and the inlet-port I) to the lower end of the cylinder will be uncovered; but by reason of the constriction or limited conducting capacity of the inlet-passage I, it will take a determinate interval of time to effect the shifting of the valve after the commencement of the transmission of steam through said passage. As is obvious, this interval will be determined by the comparative size of the said constricted inlet-passage. In order to accomplish the purpose aimed at-namely, the delay in the shifting of the valve after the exhaust port is opened until the piston shall have time to move beyond its shortest practical working-stroke to the termination of its longer strokes before steam is letinto the lower end of the cylinder-the crossarea ofthe said constrictcd assage must bear a certain relation to the diameter, weight, and length of stroke of the valve, the velocit-y of the piston, and the difference in length between its shortest and longest stroke. I find the following proportions suitable: In amachine in which the diameter of the piston is three and one-eighth inches, the entire stroke six and one-half inches, and after opening the port D one and three-quarter inch, striking four hundred to four hundred and twenty blows per minute nnder a pressure of seventy pounds per square inch above the atmosphere, and the diameter of the valve is one and a sixteenth inch, its weight seventeen inches, and its stroke five-eight-hs of an inch, the diameter of the passage II is about five thirty-seconds of an inch.

I do not intend to limit myself to the precise form or location of the described constrieted passage communicating between the steam-supply and the lower end of the valvechest. Any suitable form and arrangement for the purpose may be employed.

In the foregoing description, by the lower end77 of the cylinder I intend that toward which the piston moves in making its working-stroke. The opposite end I call-the upper end.77 3y the lower end77 ofthe valve-chest I mean that to which the valve moves in closing the inlet to the lower end of the cylinder. The opposite end I call the upper end.77

\Vhatever of novel invention is contained in the described drill other than what is specified in the claim herein I reserve for separate applications for Letters Patent.

\Vhat I claim as my invention, and desire to secure by Letters Patent, is-

In a steam rock-drill comprising the main cylinder and piston, the steam-moved valve, the described passages for distributing steam to the cylinder and valve-chest and exhausting steam therefrom, the combination, with the piston governing the exhaust-ports from the valve-chest, and the steam-moved valve governing theinlet-port to the lower end of the cylinder, of the inlet-passages to the valvechest, that establish open connnunication between the ends of the valve-chest and the live-steam supply, the saidinlet-passage leading to the lower end of the valve-chest being of comparatively small cross-area or conducting capacity, whereby there necessarily occurs a determinate delay between the opening ofthe exhaust at the upper end of the valvechest and the shifting ofthe valve to opcuthe inlet-port to the lower end of the cylinder in which the piston may move from the point ofthe shortest working-stroke, which in practice it is intended to be permitted to make, to the termination of its longer strokes, by the time the steam is admitted to the lower end of the cylinder.

Titncssesz lrlllllllRIt A. lIAhSI'lY.

A. G. N. VnnarrLrA, A. Frreri.

IIO 

